Electric fuse or cut-out.



no. 630,963. f ranma Aug. 20, 190|. L. w. Downes.

ELECTRIC FUSE 0R CUT-OUT.

(Application Med liy, 1901.)

(Ilo Nudel.)

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UNITED STATES PATENT OFFICE.

ALOUIS lV.. DOVNES, OF PROVIDENCE, RHODE ISLAND.

ELECTRIC FUSE OR CUT-OUT.

'SPECIFICATION forming part of Letters Patent No. 680,968,l dated August20, 1901.

Application filed May 2, 1901. Serial No. 58,487. (No model.)

1l) @ZZ whom if may concern:

Be it known that I, LOUIS W. DowNEs, a resident of Providence, RhodeIsland, have invented a new and useful Improvement in Electric Fuses orCut-Outs, which invention is fully set forth in the followingspecification.

The object of this invention is to provide a fuse, particularly of theplug type, adapted for use on circuits carrying electric current of highcapacity-say, for example, as high as one hundred amperes-possessingstructural compactness and simplicity enabling it to be produced andsold at a comparatively low initial cost and capable of being readilyrenewed or re-fused at slight expense after it hasburnedout.Withoutthislast-mentioned qualification the use of high-capacity fusesof this type would be prohibitive, as a repei tition of the initial costevery time the fuse burns out would probably involve greater expensethan the user could economically incur. My improved fuse comprises aninsulating-casing capable of resisting the destructive forces and gasesgenerated upon the burning out of the fuse-link and a drum or sheathremovably inserted in the casing and inclosing the fuse-link and itssurrounding non conducting heat dissipating material. The casing carriessuitable external circuitcontacts adapted to engage correspondingcontacts when in place in a socket or the like. The drum or sheath hascontacts (between which the fuse link or links are connected) adapted toengage corresponding contacts on the interior of the casing, whereby thecircuit is completed through the fuse-link.

The invention also embraces special features of construction, all ofwhich will be best understood by reference to the accompanying drawings,illustrating several embodiments of the invention, and wherein- Figure 1is an elevation, and Fig. 2 a sectional view, of one embodiment. Fig. 3is an elevation, and Fig. 4 a sectional view, of the removable drum orsheath inclosing the fuse link or links. Fig. 5 is a detail view of oneof the fuse-links, and Fig. 6 is a detail view of one of the plates towhich the fuse-links are connected. Figs. 7, 8, 9, 10, and 1l aresectional views of different forms of casings and covers therefor.

Referring to Figs. l and 2, the casing is made of a cup-like porcelainpart A, surrounded by a sleeve or shell B, of spun brass,

rolled to form a screw-thread on its exterior and constituting one ofthe exterior contacts of the casing. At its opposite extremities sleeveB has inturned lianges b b', the former bearing against the end surfaceof the porcelain cup at its open end and the latter bearing against theend surface of said cup at its closed end, thereby securing the sleeveand cup together. A metallic plate c inside of the cup A and restingagainst the bottom thereof is held in place by a screw d, having a iiathead resting against the bottom of the cup A and a screw-threaded shankpassing through said bottom and taking into plate c. The flat screw-headforming the other contact on the exterior of the casing is thuselectrically connected with the plate c, which constitutes a contact onthe interior of the casing. E is an inverted-cup-like cover for closingthe open end of cup A, consisting of a rolled screwthreaded spun-brassshell e, (forming one of the internal contacts of the casing,) coated orcovered on its exterior with an insulating material e', which shouldpossess a certain amount of resistance to heat, or, in other words, notbe readily affected by heat. For this purpose vulcabeston, porcelainenamel, vulcanite, or paper in various forms may be employed, thiscoating being securely attached to the shell. The interior screwthreadson the shell e are adapted to engage and make electrical contact withthe screwthreaded sleeve B when the cover is applied to cup A.Perforations f through the cover E at intervals about the sameconstitute vents for the escape of gas generated by the disruption ofthe fuse. Grooves g g along the inner surface of porcelain cup A formpassages leading to said vents, thus affording a ready escape for thegas generated upon the disruption of the fuse. As a considerable volumeof gas is often generated, it is necessary to thus provide vents throughwhich it may readily escape; otherwise the pressure within the casingwould be likely to explode the same.

Referring now particularly to Figs. 3 to G,

H is a perforated drum or sheath, of fibrous' material, having circularmetallic plates It h fitting in its opposite ends. Each plate h h hastwo upturned lugs h h' formed integral therewith. Two fuse-links c' il,of fusible metal, extend through the interior of the drum or sheath andare soldered at opposite ends to said lugs h h on the plates,respectively. At their middle portion the two fuselinks penetraterasmall drum lc, of paper or fibrous material, forming an air-space aboutthe fuse-links. This small drum and the air-space formed thereby may beomitted, if desirable. The interior of drum H about the fuse-linksandabout the drum 7c is filled with a non-conducting material m,preferably in a finely-divided state, (such as slaked lime,) providing amultitude of minute paths or interstices for the escape of the vapor orgas evolved upon the fusing or blowing of the Vfuse -links by anexcessive current. Drum l-l is closed at its opposite ends by brass capsn n', soldered to plates h h, respectively. When the drum is in place inthe casing, Fig. 2, cap n rests against and makes electrical contactwith the brass shell e, while cap n' rests against and makes electricalcontact with plate c. The casing being inserted into a socket havingcircuit-terminals corresponding to those on the exterior of the casing,the circuit is completed through screw d to plate c, to cap n', plate h,through fuse-links M, of any suitable form, to plate 7i, to cap n, shelle, to sleeve B. Upon the passage of an abnormal and excessive currentover the circuit the fuse-links are melted at their narrowest pointwithin the airdrum la, thus breaking the circ-uit. Any gas -generatedmakes its escape through the filling fm. and passes by way of grooves gto the vents f, as already explained. To renew the fuse, a new drum H issubstituted for that wherein the fuse-links have beenY melted.

The construction illustrated in Fig. 7 differs from that of Figs. l and2 in that foi` the all-porcelain cup A of the latter figures I havesubstituted a cup made up of a section of fiber tube o, closed at itslower end bya porcelain block o'. The liange b of shell B, engaging overthe upper end of tube o, and the flange 'b of said shell, engaging underblock o', secure the tube and block together. The liber tube may, ifdesired, be lined with .a suitable insulating material, such as mica orthin sheet-asbestos.

In the modification shown in Figs. 8 and 9 the spun-brass shell B', Fig.8, is lined vwith an insulating-covering p, such as enamel, porcelain,or mica in the form of so-called 'micanite. The cover E consists of asplinbrass screw-threaded shell q, covered with an insulating material qsimilar to those above mentioned.

Fig. 10 illustrates a construction similar to that of Fig. 7 with thefollowing exceptions, to wit: The lower part of shell B2 instead ofbeing screw-threaded is tapered between the points r and r', (to fit acorresponding taper in the socket into which the plug is to beinserted,) and screw s', seated in contact-plate t, passes outwardlythrough porcelain block r2 and a metallic contact-plate s', the latterhaving. lug s2 projecting into a ,recess s3 in the block to preventturning of the plate s as the screw s is turned through it. Theprojecting lower end of screw sis adapted to engage an interiorlyscrewthreaded opening of the socket, into which the fuse-casing is adapted tobe inserted.

The construction illustrated in Fig. 11 is similar to that of Fig. l0,except that the screw-threads at the upper part of the brass shell areomitted, and cover T has ordinary machine screw threads adapted toengage similar threads on part t of the brass shell which is bent overthe upper edge of the fiber tube and depends within the same. Ventsvthrough the fiber tube and brass shell permit the escape of gases fromwithin the casing.

What I claim as new is- 1. An electric fuse or cut-out comprising aninclosing casing, external contacts on said casing for engagement withsuitable line-terminals, and internal contacts on the casingelectrically connected with the external con` ing casing having aremovable cap or cover, external contacts on said casing for engagelmentwith suitable line-terminals, and 1nternal contacts on the casingelectrically connected with the external contacts respectively, afuse-link, an inclosing sheath therefor removably inserted in thecasing, contacts on the sheath connected by the fuselink and adapted toengage the internal con- Q tacts on the inclosing casing to complete thecircuit through the fuse-link.

3. In an electric fuse or cut-out, an inclosing casing comprising ametallic shell or sleeve constituting an external contact, an insulatingor non-conducting lining for the sleeve closed at one end, a secondexternal contact on said closed end of the lining, a removable cover forclosing the open end of the sleeve, an internal contact on and removablewith the cover and adapted to make electrical connection with themetallic shell when the cover is in place, and a second internal contactelectrically connected with the second external contact.

et. In an electric fuse or cut-out, an inclosing casing comprising ametallic shell or sleeve `constituting an external contact, aninsulating or non-conducting lining for the sleeve closed at one end, asecond extern-al contact on said closed end, an internal contactelectrically connected therewith, a removable metallic cover for closingthe-open end of the sleeve having an external covering of insulating ornon-conducting material IOO IIO

and adapted when in place to electrically engage the metallic shell andform a second internal contact.

5. In an electric fuse or cut out, an inclosing casing comprising a.metallic shell or sleeve constituting an external Contact, an insulatingor non-conducting lining for the sleeve closed at one end, a secondexternal contact on said closed end of the lining, a removable metalliccover screw threaded to electricallyT engage a screw-threaded part ofthe sleeve for closing the open end of the same, said cover having anexternal covering of insulating or non-conducting material and forming asecond internal contact.

6. In an electric fuse or cut-out, a fuse-link, an inclosing sheath forthe fuse-link, contacts on the opposite ends of said sheath betweenwhich the fuse-link is connected, a casing in which the sheathcontaining the fuse-link is removably inclosed said casing comprising acup-like part having a contact at its closed end against which thecontact on one end of the sheath bears and a cover for closing the openend of said cup-like part having a contact thereon bearing against thecontact on the other end of the sheath.

7. In an electric fuse or cut-out, an inclosing sheath of insulating ornon-conducting material for the fuse-link, metallic caps closing theopposite ends of the sheath and between which the fuse-link isconductively connected, a casing in which the sheath is removablyinclosed, said casing comprising a cup-like part and a removable coverfor closing the open end of said part, a contact-plate in the closed endof the cup-like part against which the metallic cap at one end of thesheath bears, and a contact-plate on the under side of the cover againstwhich the cap at the other end of the sheath bears, thereby completingthe circuit through the fuse.

8. In an electric fuse or cut-out, a fuse-link, a perforated tubularinclosing sheath of nonconducting material, metallic caps closing theopposite ends of the perforated sheath and conductively connected by thefuse-link, a casing in which the sheath is removably inclosed comprisinga cup-like part in which the sheath closely fits and a removable coverfor closing the open end of said part, a contactplate in the closed endof the cup-like part against which the metallic cap at one end of thesheath bears, and a contact-plate on the under side of the cover againstwhich the cap at the other end of the sheath bears, thereby completingthe circuit through the fuse.

In testimony whereof I have signed this specification in the presence oftwo subscrihing witnesses. y

LOUIS W. DOWNES.

Witnesses:

JOHN HENSHAW, EDWIN P. ALLEN.

